The term 'TRIANGULAR STREET SIGN' refers to a type of traffic sign that is shaped like a triangle and is used to indicate that drivers must YIELD the right-of-way to other vehicles or pedestrians. The crossword solution for this term is 'YIELD', which is a verb meaning to give way or to surrender possession or control. Yielding is an important part of driving safety, as it allows drivers to avoid collisions with other vehicles or pedestrians.